Presently, there exist many types of inflators designed to inflate inflatable devices such as life jackets, life vests, emergency signaling equipment, and the like. Inflators typically comprise a body for receiving the neck of a pressurized container of compressed fluid such as carbon dioxide. A puncture pin is held within the body of the inflator for piercing the friable seal of the container to permit the compressed fluid therein to flow into a manifold and then into the device to be inflated. Typically, a manually movable lever is connected to the puncture pin such that the puncture pin pierces the friable seal of the container upon a jerking motion of the lever.
In the case of an inflatable life jacket, manually operated inflators require an intention by the wearer to activate the inflator to release the compressed fluid to inflate the life jacket. If the wearer is disabled or unconscious, he or she may be unable to manually activate the inflator.
In response to this problem, automatic inflators have been created to, singly or in combination with a manual lever, automatically inflate a device when exposed to a fluid such as water. Some of these automatic inflators utilize probes or a conductor mounted in the inflatable device. The probes or conductors form a part of an electrical circuit used to automatically drive a puncture pin into the pressurized fluid container. When the housing is fully submerged in water, a circuit is closed between the probes which supplies electric power to the actuating mechanism.
While such inflators may be an improvement over entirely manually activated inflators, care must be taken to prevent water from entering the circuitry and cause premature activation due to a splash of water when the housing is not fully immersed in water or from the housing being in a very moist environment.
In response to this realized inadequacy of the prior art manual inflators, water activated automatic inflators were developed which, when exposed to a fluid such as water, automatically activated the piercing pin of the inflator when immersed in water thereby causing inflation of the inflatable device. In these devices, the automatic inflator includes a water-activated trigger assembly wherein a water-destructible element retains a spring loaded actuator pin in alignment with a puncture pin. Upon exposure to water, the element dissolves, and the spring-loaded actuator pin is released to forcibly move from the cocked position to strike the puncture pin. Upon striking the puncture pin, the pin fractures the seal of the container thereby allowing the compressed gas to escape and inflate the inflatable device. A majority of these automatic inflation devices utilize a water-soluble tablet to trigger the activation of the automatic inflation device. These tablets are similar to an aspirin both in appearance and physical properties. Two of their physical characteristics that enable them to be used for this purpose are; 1) they quickly lose their structural integrity when exposed to water 2) they are able to with stand considerable forces without fracturing when kept relatively dry.
The tablet, which consists of a desiccant material, immediately looses its ability to sustain any load when-submerged in water. However, when exposed to high humidity environmental conditions, the tablet will absorb moisture which produces a progressive degradation of the tablets load supporting properties. The rate at which the moisture is absorbed is a function of the relative humidity and ambient temperature. The amount of moisture that has been absorbed is a function of the length of time the tablet is subjected to the particular environmental conditions. The fracture strength of the tablet is directly related to the amount of moisture that has been absorbed. For example; if two identical tablets are simultaneously subjected to the same high humidity ambient conditions and physically subjected to the same type of compressive load only the magnitude of the load on one tablet is greater than that on the other, the tablet having the largest loaded will fracture first, i.e., in the shortest period to time. This loss of strength as a function of the amount of moisture absorbed, explains the need to minimize the magnitude of the load on the tablet in order to extend the time that the device can operate in a high humidity environment without a false activation.
It is thus necessary to develop an apparatus which can significantly reduce the force acting on the tablet while in the armed state, if one is to extend the operating life of the automatic inflation device in the presence of high humidity.
Accordingly, as set forth above, a major disadvantage of the known inflators is premature activation in non-emergency situations. The problem of unintentional activation is so acute that it is not uncommon to have to replace the destructible element on a regular basis when the inflator is stored in high moisture conditions, such as with a life jacket on a boat. Moreover, the problem of prematurely and unintentionally activated automatic inflators is so acute that it is not uncommon to be readily replacing the water destructible elements and resetting the automatic inflators on a regular basis when the inflators are constantly stored around water. It is noted that each of the prior art water activated automatic inflators disclosed in the above referenced patents describe a procedure by which the automatic inflator can be disassembled to facilitate the replacement of the water destructible element and gas-containing capsule so that the inflator may be reused.
Particularly with regard to entirely mechanical inflators, reasons for unintentional activation include insufficiently protecting the destructible element from conditions that cause it to degrade and excessive forces generated by the potential energy stored within the inflator applied directly to the destructible element.
In the patent arts, there have been numerous patents that disclose various types of automatic inflation devices For example, water activated automatic inflators have been disclosed in prior patents whereby a water activated trigger assembly is featured which includes a water destructible or dissolvable element which retains a spring-loaded actuator pin in a cocked position in alignment with a piercing pin. In these devices, upon exposure to water which causes the element to destruct or dissolve, the spring loaded actuator pin is released to forcibly move from the cocked position to an actuated position to strike the piercing pin, either directly or indirectly by means of an intermediate transfer pin. The piercing pin will thus fracture the seal of the cartridge thereby allowing the gas contained therein to flow into the inflatable device in order to inflate it. Representative patents which feature such automatic actuators for inflators having water dissolvable elements include U.S. Pat. Nos. 3,059,814, 3,091,782, 3,426,942, 3,579,964, 3,702,014, 3,757,371, 3,910,457, 3,997,079, 4,223,805, 4,267,944, 4,260,075, 4,382,231, 4,436,159, 4,513,248, 4,627,823, and 5,076,468, and all of the disclosures of these patents are hereby incorporated by reference herein. However, none of these patents features systems which provide added protection against the unintended degradation of the dissolvable element and the unwanted firing of the inflation device.
Still other patents in this field include U.S. Pat. Nos. 2,946,484; 3,809,288; 3,815,783; 3,934,292; 4,191,310; 4,500,014; 4,356,936; 5,816,878; 5,419,725; 5,582,494; 6,561,863; 6,589,087; 5,694,986; 5,601,124; 5,775,358; 5,035,345; 4,972,971; 6,659,824; and 6,394,867; U.S. Pat. App. Pub. Nos. 2004/0124209; 2003/0049982; and 2003/0049981; and European Patent Application No. 598,601, all of said patent references being incorporated herein by reference.
Therefore, what is needed is a device that, among other advantages, will significantly reduce the forces applied thereto, thereby extending the operating life of the automatic inflation device in the presence of high moisture.